The present invention relates to an apparatus for controlling a load handling device that is provided in an industrial vehicle.
Forklift trucks have been used widely as an industrial vehicle that performs load handling operations (picking up and placing of loads) in a warehouse. In a forklift truck, operation of lifting the forks having thereon a load with the mast assembly tilted forward may affect the operational stability of the forklift truck. Japanese Unexamined Patent Application Publication No. 2001-206695 discloses an overturning alarm device for an industrial vehicle. The tilt angle of the mast assembly of the industrial vehicle is determined based on the detected tensile force acting on the tilt cylinder that causes the mast assembly to tilt and an alarm is issued when the tilt angle of the mast assembly exceeds a predetermined value.
In addition to issuing an alarm, a method for regulating the lifting speed of the forks when the tilt angle of the mast assembly exceeds a predetermined angle has been proposed in the art. According to this method, the regulated lifting speed of the forks is felt by an operator of the forklift truck, who is then prompted to tilt the mast assembly backward.
However, regulating the lifting speed of the forks poses a drawback in that the working efficiency of the forklift truck in the load handling operation may be lowered. Therefore, the lifting speed of the forks should preferably be not regulated as long as operational stability of the forklift truck is secured.
The present invention is directed to providing an apparatus for controlling a load handling device in a forklift truck that enhances the operational stability of the forklift truck while maintaining the working efficiency in load handling operation.